It seems that the popular way of modifying a solenoid sprinkler valve for better performance is to tap a pilot valve out that releases air pressure by means of a manual blow gun. This method basically bypasses the electric solenoid triggering.

For personal reasons, I want an electric triggering setup, but one that far surpasses the performance of a regular non-modded solenoid valve, or perhaps one that even surpasses the performance of a manual blow gun pilot valve-modded valve.

So here's what I was thinking: A solenoid valve that has a modified pilot valve hole, going the blow gun-tapping method. The only difference would be, rather than using a "manual" blow gun outlet to release pressure in the upper chamber of the main valve, I would replace the blow gun outlet with a connection that leads to "another" solenoid valve.

Basically, you would be using the electric trigger of the second (non-main) valve to actuate the pressure relief of the main modded valve.

So my questions are:

1) Wouls this even work?

2) Has anyone here tried this before?

3) Would this perform better that a manual blow gun mod. or at least better than?

Now for me, this mod would only be worth it if it at least performs close to a manual blow gun mod.

So you think that it might perform as well as a normal "modded" sprinkler valve, as in a "sprinkler valve modded with a blow gun pilot"?

If so, then that would be more than beneficial for me.

I don't really care about the extra cost and/or bulk of including a secondary solenoid sprinkler valve. I just need something electrical that performs "close to" or perhaps better than the blow gun mods.

Yes, it will work but you have to figure that you are spending another 15 bucksish on another sprinkler valve instead of 4 bucks on a blowgun.

I have not personally seen any mods that enlarged the holes for the actual solenoid and remained electric. It is an interesting idea. Those holes are that size to avoid "water hammer" to the sprinkler units. Being that small they leak slowly. When the valve opens, it opens, don't get me wrong, but the valve leaks or wastes more air doing so compared to a blowgun.

I would be interested to know if it is possible to enlarge those ports and still use the factory solenoid. My only doubt is whether or not an Orbit Watermaster can be used. The following pic shows the inside of the port from the modding thread. You see the little white plastic job in the middle of the port. That piece is cone shaped and almost pointy where the solenoid seats. If you go enlarging that I don't think the solenoid will seat properly, even less so if you don't enlarge it centered square.

This next pic is from my thread on modding a Rainbird valve. You can see the same ports on this but this valve has a fatter and flat seat for the solenoid. I think you would have an easier time enlarging this port and still getting a good seal. (pic is bigger if you click it to enlarge)

Ultimately, I for one, would be interested to hear your results if you do decide to go for the modding the solenoid openings.

hubb017 wrote:Yeah, I have never tried it (due to cost and bulk ) but I don't see why it would not perform as well as a regular modded sprinkler valve.

Hub, when you refer to "regular modded valve", you do mean a valve that is modded with the manual blow gun, right?

And yes, people usually suggest to try out theories to see if they work. I will be experimenting soon. I just wanted to get some heads-up before I do anything. ...basically trying to research and receive advice/experience from others.

I know it's more money/time/effort but I'd consider building a small (1/2" or smaller) piston valve, or finding a 1/4" QEV for your pilot, which would be piloted by the sprinkler's original solenoid. This would give you great performance and electronic piloting abilities - plus, you could use your mini-piston or QEV as the pilot on your next cannon, too (electronically actuated piston valve anyone?).

Yes, it will work but you have to figure that you are spending another 15 bucksish on another sprinkler valve instead of 4 bucks on a blowgun.

I have not personally seen any mods that enlarged the holes for the actual solenoid and remained electric. It is an interesting idea. Those holes are that size to avoid "water hammer" to the sprinkler units. Being that small they leak slowly. When the valve opens, it opens, don't get me wrong, but the valve leaks or wastes more air doing so compared to a blowgun.

I would be interested to know if it is possible to enlarge those ports and still use the factory solenoid. My only doubt is whether or not an Orbit Watermaster can be used. The following pic shows the inside of the port from the modding thread. You see the little white plastic job in the middle of the port. That piece is cone shaped and almost pointy where the solenoid seats. If you go enlarging that I don't think the solenoid will seat properly, even less so if you don't enlarge it centered square.

This next pic is from my thread on modding a Rainbird valve. You can see the same ports on this but this valve has a fatter and flat seat for the solenoid. I think you would have an easier time enlarging this port and still getting a good seal. (pic is bigger if you click it to enlarge)

Ultimately, I for one, would be interested to hear your results if you do decide to go for the modding the solenoid openings.

Yeah, and as far as actually enlarging the solenoid pilot valve, I pondered about that option during the early stages of my brainstorming. I decided to ditch that idea though, because I did not want to jeopordize the quality of the end-resulting seal of the solenoid. I figured that the manuafacturer has the solenoid precisely made to seal that tiny area and so I did not want to mess around with trying to "rebuild" it to make it seal a larger hole.

That's when the blow gun method crossed my mind. Basically I would remove the solenoid altogether and seal up it's pilot hole with epoxy. Then tap the upper valve chamber with a 1/4" connection (or larger) that would lead to another valve (another solenoid valve to be exact) that is in place of the typical blow gun. So I would be going the blow method, but without actually using a blow gun.

As far as what you mentioned about the (solenoid) valve (pilot) "leaking" or "wasting" more air, that problem can be solved:

Basically the outlet of the pilot valve could be connected back into the pressure chamber (I'm not even sure if that would work or have any drawbacks). If that doesn't work, then the pilot outlet can be connected into the "main" valve's output, much like how the orginal design of the solenoid valve works -- original solenoid pin-sized pilot hole exits into valve output.

I actually believe it might be possible with the Rianbird to enlarge the holes in the solenoid system for increased flow and faster activation. I have to make a run through Menards tonight so I'll grab another valve and check it out. The solenoid on the Rainbird is huge in comparison to the Orbit, and the base/sealing face is basically the whole face at the bottom of the threads in the picture from my earlier post. My only question is whether or not the inlet port to the solenoid could be enlarged.

As to running the exhaust from the solnoid or blowgun back into the chamber, I don't think that will work since the air in the blowgun or exhaust line will be at less psi than the tank due to distance. There has been talk in other threads about harnessing that air for cycling a bolt or filling a secondary tank for various purposes, but back into the main firing tank won't work.

You can "port out" the pilot whole on most stock sprinkler valves. For these valves, opening speed probably was not a design consideration. So the engineer really didn't care how fast the valve opens, since in the designed use it doesn't really matter if they open fast or slow. (It does matter that they close slow to prevent water hammer, but water hammer only occurs when a valve closes, not when it opens.)

I ported out my 3/4" rainbird by simply redrilling the hole a bit. Doesn't take much of an increase in the diameter of the whole to significantly increase the area (hence the flow) of the hole. The hole is pretty small to start with, IIRC less than 1/16"D.

Unfortunately, I did this a long time ago, before I had a chronometer. So I have no idea how much it affected the performance of the valve. Might be an insignificant increase, might be a substantial increase, really don't know.

It is also possible to port a blow gun. I believe the bore hole on a typical blowgun is ~1/8"D. No reason it can't be drilled out to a bit bigger.

The Rainbird CP-100, like I did a mod program on has a sealing face that is the size of the bottom of the threads of the solenoid. More than adequate to seal the port even with an enlarged hole. The Orbit is like I said, with a smaller and almost pointy port, the seal on the Orbit is also significantly smaller.

You could probably drill out the vertical or outlet port on the Rainbird quite a bit. The inlet port from the top chamber would be more difficult to drill due to the angle but that could be basically any size you wanted it to be as there is more than enough room to enlarge that one.

I currently don't have access to a chrono. I will by next spring, so I guess we will find out then if not sooner from someone else.